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PatrickV

GH4 & Audio recording met external mic

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Hi there,

 

I'm testing the GH4 with my Sennheiser MKE 400 external mic.

 

It seems that my recorded audio is not loud enough. The audio level monitor on the GH4's screen barely comes to the center of the audio level monitor.

 

I have a few questions:

 

  • How can I get my audio recorded much louder?
  • I've already set the mic level to +6dB. Is it safe to use this setting anyway?

 

Thanks in advance!

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Use a mic preamp.  Something like

 

Hi there,

 

I'm testing the GH4 with my Sennheiser MKE 400 external mic.

 

It seems that my recorded audio is not loud enough. The audio level monitor on the GH4's screen barely comes to the center of the audio level monitor.

 

I have a few questions:

 

  • How can I get my audio recorded much louder?
  • I've already set the mic level to +6dB. Is it safe to use this setting anyway?

 

Thanks in advance!

 

Use a mic preamp.  Something like Zoom H4N (or the new H5N) and a bunch of TASCAM units could help.  If you have money, a Sound Device MixPre-D is also a good choice.

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That is an option, but I prefer to record my audio in camera.

 

The strange thing is that my mic levels are almost in the red zone (at my GH4) but the volume of my audio files on my computer is a bit low.

How can I resolve this?

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@PatrickV when you say the volume is a little low on your computer, what precisely are you referring to? The computer's built-in speakers? The level meters on your NLE? I will second the external recorder recommendation. And I would try to keep recorded levels between -6-~-12 dB. You can never remove distortion from your clips. 

 

/edit/I guess it pays to read the original post carefully before replying :) There isn't any harm in using the external microphone's level boost. Some manufactures even recommend doing so to avoid using the camera's mediocre audio circuitry. So what you are saying is that with the external mic set at +6, your GH4 is showing clipping, yet the NLE meters are showing that the audio levels are safe? That is perfectly normal. On my GH3, I often see the same thing. Still, not certain what you mean by 'not loud enough', though: your computer's built-in speakers; as heard through a set of earphones; or the NLE's audio meter. You can always raise levels in post, but you can never remove distorted sound resulting from clipping. 

 

/edit2/what exactly is it that you are recording?

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Thanks for your comments!

 

External recording is not really an option for me since I would like to stay mobile on location.

 

The point is that, when shooting interviews with my GH4 the mic levels reach the red levels all the time. So I set the mic level adj (in camera) to -6 dB or even -12 dB. The mic levels didn't reach the red area anymore, but my audio sounds less 'rich'. I've made a comparison of an interview with my GH2 and my new GH4 (same external mic). See and listen: 

 

 

The recorded sound on my GH2 sounds much 'richer', do you agree?

 

I just tried the following:

 

GH4 mic level adj: 0 dB

Sennheiser ew 122-p G3: 0 dB

 

But: mic level limiter ON

 

Now my audio levels hardly reach the red area and sounds 'richer'. Is this the best solution for me? What do you guys think?

 

Thanks in advance.

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The GH2 sounds much clearer in the test you posted. There is a distorted 'edge' to the sound with the GH4. You don't want the meters to touch red, and I've found that to be particularly true with speech. In music, it is sometimes unavoidable, and can pass largely undetected, but distortion is unmistakable in interviews.

 

PS How can we know if your solution is the answer if we can't hear it? Give us another sample! :)

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Here you go! 

 

I think this sounds much better. What is the best workflow to match the 'less rich' sound to my good audio in post? Simply raise the db?

 

Thanks in advance.

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If by less rich sound, you are referring to the earlier, distorted recording, raising levels in post will only worsen matters.... If on the other hand, you mean your most recent recording, you can just raise the levels a bit in post. That's why you want to remain in the -12 to -6dB range when recording - there is still some latitude for adjustment in post. Below -16dB, and it will be too noisy. If you want warmer sound, maybe tweak equalization. In any case, the newer sound is a big improvement.

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If by less rich sound, you are referring to the earlier, distorted recording, raising levels in post will only worsen matters.... If on the other hand, you mean your most recent recording, you can just raise the levels a bit in post. That's why you want to remain in the -12 to -6dB range when recording - there is still some latitude for adjustment in post. Below -16dB, and it will be too noisy. If you want warmer sound, maybe tweak equalization. In any case, the newer sound is a big improvement.

 

I don't know if the GH4 records audio in 16 or 24 bit, but that will affect where you want your audio to be peaking. If it does indeed record in 24-bit, then you are fine with your audio levels hitting around -12dB. If, however, you can only record in 16-bit, you will want to get your levels closer to -6dB, because you won't be able to apply gain as cleanly.

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I don't know if the GH4 records audio in 16 or 24 bit, but that will affect where you want your audio to be peaking. If it does indeed record in 24-bit, then you are fine with your audio levels hitting around -12dB. If, however, you can only record in 16-bit, you will want to get your levels closer to -6dB, because you won't be able to apply gain as cleanly.

I was just about to say the same thing: higher bit rate, more headroom. I even looked up the GH2 user manual, but I couldn't find any information about the audio. There were only 208 pages in that manual, though :)

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I have done and still do sometimes 16/44 recording and it sounds pretty full because the mic quality and the mic pre is good. The bit depth and sample rate only becomes the barrier if it is below 16/44 (like 12 bit in some older camcorders, etc.). One of the big issues that people don't come across sorting it is the impedance matching. If the impedance of the source (output) is in a certain proportion with the impedance of the receiver (input) then it's perfect sounding. If not, either there is going to be a lot of noise floor with a full sound, or a thin sound. The optimum impedance sounds full but with minimal noise.

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